Electrochemical devices, such as proton exchange membrane fuel cells, sensors, electrolyzers, chlor-alkali separation membranes, and the like, have been constructed from membrane electrode assemblies (MEAs). An MEA used in a typical electrochemical cell, for example, includes an ion conductive membrane (ICM) that is in contact with catalyst-containing anode and cathode electrode layers. The ICM typically comprises a polymeric electrolyte material, which may constitute its own structural support or may be contained in a porous structural membrane.
The anode/membrane/cathode structure is sandwiched between two microporous, electrically conductive elements called diffusion current collectors (DCCs) to form a five layer MEA. Ions formed at the anode are transported to the cathode, allowing current to flow in an external circuit connecting the electrodes.
Catalyst layers have been formed using nanostructured support elements bearing particles or thin films of catalytic material. The nanostructured catalyst electrodes may be incorporated into very thin layers forming a dense distribution of catalyst particles on the ICM surface.
Effective MEA design strives toward increased interfacial area contact between the various layers of the MEA sandwich in order to effectively facilitate the transport of reactants and byproducts through the MEA. Increased interfacial area provides a higher efficiency and increased current carrying capacity.
The present invention describes an enhanced interface for MEA subassemblies and provides methods of making the enhanced interface.